The proposed clinical trial will evaluate immunogenicity of E75 peptide vaccine in women with ductal carcinoma in situ in comparison to GM-CSF alone. It is a pre-surgical/ post-surgical phase IIb, randomized, multi-center study for women with histologically confirm ductal carcinoma in situ. HLA-A2+ participants who meet all other eligibility criteria will be randomized to receive NeuVaxTM (nelipepimut-S; 1000 ?g of E75 and 250 ?g of GM-CSF) or GM-CSF alone. Patients randomized to the nelipepimut-S + GM-CSF arm will receive three vaccinations of nelipepimut-S (1000 ?g) and GM-CSF (250 ?g) administered intradermally two weeks apart prior to surgery, and three vaccinations 1 month apart post surgery for six total vaccinations.